GCHQ has been threatened with cyber-attack tomorrow

The ability of the UK's security institutions to fight off the threat from online activists was cast into doubt after hackers penetrated Scotland Yard's anti-terrorism hotline and leaked conversations between staff online.

The ability of the UK's security institutions to fight off the threat from online activists was cast into doubt after hackers penetrated Scotland Yard's anti-terrorism hotline and leaked conversations between staff online.

Britain is lagging behind the US, France and Germany in its capacity to respond to cyber attacks, a former senior official at the government "listening post", GCHQ, warned yesterday.

Two hackers, aged 16 and 17 and living in the West Midlands, were detained last night over the security breach, as another hacking group, which attacked a host of government websites last week, vowed to resume its offensive this weekend with attacks on GCHQ and the Ministry of Justice.

Scotland Yard said it was investigating the attack after one activist listened in on a conversation between anti-terrorist officials and posted the results online. The hackers also "phone-bombed" the hotline with 700 calls. The group, an international team of eight known as "TeaMp0isoN", who claim never to have met, told The Independent newspaper that it was easy to break into the "very old" phone system to record the conversation, in which an official briefed a colleague about the "phone-bomb" attack.

The attack raises questions about national security and the level of telecommunications security at Scotland Yard after hackers from another group, Anonymous, broke into a conference call in February instigated by the FBI and published the discussion online. Professor Anthony Glees, director of the Centre for Security and Intelligence Studies at Buckingham University, said the fact that "cyber terrorists" have sufficient technical skill to "potentially disrupt the process of democratic governance" was "seriously worrying".

"The same sort of thing could cause chaos in an Olympic and Jubilee year," he said, adding that it showed why the Government wants to allow police and security services greater powers to trawl private email accounts. "At the moment, the authorities can't do anything about it."

Members of 'hacktivist' group Anonymous told The Independent they intended to wage a sustained campaign in protest at decisions to extradite British citizens to America and the Government's email-surveillance plans.

One of the founders of the group, known only as TriCk, posted a conversation between a hacker and a Scotland Yard terror official. The caller – who has an American accent but claims to be living in Britain – tells the official: "Knowledge is power. We embarrass governments and f*** the police."

The group, which emerged in 2009, has attacked the websites of, or exposed personal information about, Nasa, the former prime minister Tony Blair, BlackBerry and the United Nations.

"We looked more into the actual phone system they were running; it was very old and we found a way to get in... which allowed us to listen in," TriCk told The Independent, adding there was "more to come".

Ailsa Beaton, director of information for the Metropolitan Police, said the force was confident its communications systems remained secure. But Peter Wood, head of the ethical-hacking firm First Base Technologies, said "telephone systems are inherently not very secure".

Nick Hopkinson, former chief information officer at GCHQ, told Computing magazine that Britain's fragmented approach to cyber security had left it trailing other nations.

A spokesman for the Ministry of Justice said: "We take the security of our website extremely seriously and we are working with our suppliers to minimise the risk to the site from future attacks." A spokesman for GCHQ did not respond to a request for comment.

Team Poison: Who's been tricked?

Team Poison is a network of young, politically minded hackers who have launched a string of attacks against websites and fellow cyber activists. In December 2010 they broke into the servers of the English Defence League and published their entire membership list. Other hacks, such as those targeting the website of the Indian politician Rahul Gandhi, revealed that the group has strong pro-Gaza and pro-Kashmir stances.

Last year The Independent revealed how Team Poison, whose members have never met, was co-ordinated by a British-based Muslim teenage hacker known online as TriCk. The group has eight current members, he said yesterday.